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Phoenix Introduction

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Hardware and Architecture

The HLRS DGRID Cluster platform consists of one front node for interactive access (forntend.dgrid.hlrs.de) and serveral compute nodes for execution of parallel programs.

Two different compute node CPU architecture types are installed:

  • IBM cell
  • Intel Xeon 5150 (woodcrest)


  • Operating System: ScientificLinux 4.4 on Intel based nodes
  • Operating System: Fedora Core5 on cell based nodes
  • Batchsystem: Torque/Maui
  • node-node interconnect: Infiniband + GigE
  • Local Disk for scratch on each node
  • Global Disk 100 TB
  • GPFS
  • OpenMPI
  • Compiler: Intel, GCC, Java

Short overview of installed nodes
Function Name CPU Memory Disk PBS properties Interconnect
Compute Nodes node01 - node28 Intel Xeon 5150 2.66 GHz 8 GB 160 GB dgrid GigE/Infiniband
Compute Nodes cell01 - cell07 Cell Broadband Engine 3.2 GHz 1GB 40 GB cell GigE/Infiniband
Login Node frontend Intel Xeon 5150 2.66 GHz 16 GB 250 GB - GigE/Infiniband
I/O Server data1 / data2 Intel Xeon 5130 2.0 GHz 16 GB 100 TB - GigE/Infiniband
Infrastructure (NTP,PBS,DNS,DHCP,FTP,GT4,...) some virtual XEN based hosts) Intel Xeon EM64T 3.4 GHz 8 GB 270 GB - GigE


The only way to access frontend.dgrid.hww.de (frontend node of HLRS DGRID Cluster) from outside is through ssh


The frontend node


is intended as single point of access to the entire cluster. Here you can set your environment, move your data, edit and compile your programs and create batch scripts. Any interactive usage of the frontend node which causes a high cpu/memory load are NOT allowed (production runs).

The compute nodes for running parallel jobs are available only through the Batch system on the frontend node.

HOME Directories

All user HOME directories for every compute node of the cluster are located on the I/O Server data1.dgrid.hlrs.de. The compute nodes and login node (frontend) have the HOME directories mounted via NFS. On every node of the cluster the path to your HOME is the same. The filesystem space on HOME is limited by a quota of 700MB! Please note the Filesystem Policy!

SCRATCH directories

Local Scratch

Global Scratch

Environment Settings

In order to use some software features like special MPI versions, or Compilers, you have to perform some environmental settings. To modify the default HLRS DGRID environmental settings on login, you can create a file $HOME/.profile which contains your own envirenmental settings. The login shell is a bash shell which reads $HOME/.profile during login!

Environment Settings using command module

The environmental setting using this methode will not be saved and will be lost for a new session. A new session (login, new job) will have the default HLRS DGRID environment. The Cluster system uses modules in the user environment to support multiple versions of software, such as compilers, and to create integrated software packages. As new versions of the supported software become available, they are added automatically to the programming environment, while earlier versions are retained to support legacy applications. By specifying the module to load, you can choose the default version of an application, or another version. Modules also porvide a simple mechanism for updating certain environment variables, such as PATH, MANPATH, and LD_LIBRARY_PATH. The following topics describe the fundamentals of using the modules environment.

  • to invoke the module command, type:
    module option args
    module help modulecommand
    The help command will provide more detailed information on the specified module. Without argument modulecommand you will get online help for the module command.
    module avail
    The avail option displays all the modules that are available on the system. Where there is more than one version of a module, the default version is denoted by (default).
    module list
    The list option displays all the modules that are currently loaded into your user environment.
    module add / module load modulename
    The add option and the load option have the same function - to load the specified module into your user environment.
    module rm / module unload modulename
    The rm option and the unload option have the same function - to unload the specified module from your user environment. Before loading a module that replaces another version of the same package, you should always unload the module that is to be replaced.
    module display modulename
    The display option shows the changes that the specified module will make in your environment, for example, what will be added to the PATH and MANPATH environment variables.
    module switch modulename/currentversionmodulename/newversion
    The switch option replaces the currently loaded version of a module with a different version. When the new verion is loaded, the man page for the specified software will also be updated.

  • using $HOME/.modulerc
    This file can be used to load or to define your own environment during each login. An example looks like this:
    set version 1.0
    module load use.own

Filesystem Policy

IMPORTANT! NO BACKUP!! There is NO backup done of any user data located on HLRS DGRID systems. The only protection of your data is the redundant disk subsystem. This RAID system (Raid5) is able to handle a failure of one component (e.g. a single disk or a controller). There is NO way to recover inadvertently removed data. Users have to backup critical data on their local site!